CAPSULE HOLDER FOR ROTARY MIXING DEVICE

PORTE-CAPSULE POUR MELANGEUR ROTATIF

English Abstract

A capsule holder for retaining a mixing capsule on a
rotary mixing device includes a carrier plate 10, an actuator
disk 11 rotatable relative to the plate, and two retaining
arms 12, 13 for clamping the capsule from opposite sides, the
retaining arms having driving pins 22 engaging spiral cam
slots 26 of the actuator disk 11. By rotating the actuator
disk 11, the retaining arms 12, 13 are moved away from, or
toward, each other. The thus constituted gearing is
self-locking in one direction of force transmission so that
centrifugal forces exerted on the retaining arms 12, 13 during
rotation cannot move the arms apart. On the other hand, the
retaining arms 12, 13 are opened with little effort by
rotating the actuator disk 11.

Claims

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Claims
1. A capsule holder for a rotary mixing device, the capsule
holder comprising:
a carrier portion adapted to be coupled to a rotary part
of the mixing device,
a pair of retaining members movable relatively to each
other along a capsule clamping direction and disposed on said
carrier portion for engaging a capsule from two opposite
sides along said clamping direction, and
an actuator member mounted on said carrier portion for
movement relative to said carrier portion and to both of said
retaining members,
said actuator member including guide means for at least
one of said retaining members, said guide means extending at
an angle with respect to both the direction of movement of
said actuator member and said clamping direction, movement of
said actuator member relative to said carrier portion causing
both of said retaining members to move relative to each other
and to said actuator member.
2. The capsule holder of claim 1, wherein said guide means
extends at an angle with respect to said clamping direction
which is larger than the angle at which said guide means
extends with respect to the direction of movement of said
actuator member.
3. The capsule holder of claim 1 or 2, wherein said
actuator member is in engagement with both of said retaining
members through said guide means.
4. The capsule holder of claim 1, wherein said actuator
member is resiliently biased toward a position in which it
urges said retaining members toward each other.

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5. A capsule holder for a rotary mixing device, the capsule
holder comprising:
a carrier portion adapted to be coupled to a rotary part
of the mixing device,
a pair of retaining members movable relatively to each
other along a capsule clamping direction and disposed on said
carrier portion for engaging a capsule from two opposite
sides along said clamping direction, and
an actuator member mounted for rotation relative to said
carrier portion about a common axis and being in engagement
with at least one of said retaining members through guide
means which extends at an angle with respect to both the
direction of movement of said actuator member and said
clamping direction, rotation of said actuator member relative
to said carrier portion causing both of said retaining
members to move relative to each other and to said actuator
member.
6. A capsule holder for a rotary mixing device, the capsule
holder comprising:
a carrier portion adapted to be coupled to a rotary part
of the mixing device,
a pair of retaining members movable relatively to each
other along a capsule clamping direction and disposed on said
carrier portion for engaging a capsule from two opposite
sides along said clamping direction, and
an actuator member mounted on said carrier portion, said
actuator member being movable relative to said carrier
portion and being in engagement with at least one of said
retaining members through guide means which extends at an
angle with respect to both the direction of movement of said
actuator member and said clamping direction,
wherein said actuator member is mounted for rotation
relative to said carrier portion and has a spiral cam

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arrangement, and said retaining member has a follower
engaging said cam arrangement.
7. The capsule holder of claim 6, wherein said spiral cam
arrangement is so shaped that said retaining members are
moved away from each other when said actuator member is
rotated in a direction opposite to the rotational direction
of the mixing device.
8. The capsule holder of claim 6, wherein said cam
arrangement extends through an angle substantially between
45° and 180°.
9. A capsule holder for a rotary mixing device, the capsule
holder comprising:
a carrier portion adapted to be coupled to a rotary part
of the mixing device,
a pair of retaining members movable relatively to each
other along a capsule clamping direction and disposed on said
carrier portion for engaging a capsule from two opposite
sides along said clamping direction, and
an actuator member mounted on said carrier portion, said
actuator member being movable relative to said carrier
portion and being in engagement with at least one of said
retaining members through guide means which extends at an
angle with respect to both the direction of movement of said
actuator member and said clamping direction,
wherein said carrier portion is formed as a disk having
a guide slot for each of said retaining members, said slot
being open at the periphery of said disk.
10. The capsule holder of claim 9, wherein said disk has an
outward sloping peripheral portion within the area of said
guide slot.

Description

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Background of the Invention
Rotary mixing devices, such as known from U.S. Patent No.
5,167,448, are used for intensively mixing material compo-
nents, specifically dental substances consisting of two or
more components. In the known device, a capsule containing
the substance is placed in a holder which is mounted on a
rotary disk at an eccentric position with respect to the disk
axis and so that the holder is rotatable about it own axis .
The known mixing device is capable of performing both a mix-
ing step proper, in which the capsule is moved back and forth
1o due to its own rotation on the ratary disk, and a centrifug-
ing step, in which the capsule itself does not rotate rela-
tive to the rotary disk and the substance is compressed in
the direction of a dispensing piston provided within the cap-
sule.
Conventional capsule holders for dental mixing devices
are fork-shaped and consist of two leaf springs or of a rigid
member and a resilient member, between which the capsule is
clamped. U.S. Patent No. 4,890,931 discloses a capsule holder
of this type, which comprises a carrier portion adapted to
2o the coupled to a rotary part of the mixing device, and a pair
of retaining members movable relatively to each other along a
capsule clamping direction and disposed on said carrier por-
tion for engaging a capsule from two opposite sides along
said clamping direction.
The known mixing forks require a comparatively large
amount of space, specifically in the direction perpendicular
to the capsule axis (which is usually the axis along which
the mixing movement takes place). Further, they are unsuited
for the rotary mixing devices described above because they
3o fail to retain the capsule with sufficient safety during the
mixing and centrifuging steps, in which forces exerted on the
capsule are not only in the clamping direction.

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Summary of the Invention
It is an object of the invention to provide a capsule
holder which is easy to handle and capable of reliable
retaining of the mixing capsule, thereby being specifically
suited for rotary mixing devices.
To meet this object, the invention provides a capsule
holder for a rotary mixing device, comprising a carrier por-
tion adapted to the coupled to a rotary part of the mixing
device, a pair of retaining members movable relatively to
to each other along a capsule clamping direction and disposed on
the carrier portion for engaging a capsule from two opposite
sides along the clamping direction, and an actuator member
mounted on the carrier portion and being movable relative to
the carrier portion and being in engagement with at least one
i5 of the retaining members through guide means which extends at
an angle with respect to both the direction of movement of
the actuator member and the clamping direction.
In the capsule holder of the invention, the capsule is
clamped between the retaining members by means of a gearing
2o rather than by spring force in such a manner that moving the
capsule retaining member or members is readily possible by
the actuator member, while the actuator member is substan-
tially more difficult to move, if at all, by the retaining
members .
25 The guide means preferably extends at an angle with
respect to the clamping direction which is larger than the
angle at which the guide means extends with respect to the
direction of movement of the actuator member. This structure
results in a self-locking type of gearing.
3o In a preferred embodiment, the actuator member is in en-
gagement with both of the retaining members through the guide
means. The retaining members thus move symmetrically so that
the centre of gravity of the capsule holder remains substan-
tially constant irrespective of the size of the capsule.
35 In accordance with another embodiment, actuator member is
resiliently biased toward a position in which it urges the

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retaining members toward each other. Thus, the capsule is
clamped even without manual movement of the actuating member.
Since the resilient force only has to move the easily movable
actuating member without having to withstand any forces
s occurring during the mixing step, it may be correspondingly
weak. Therefore, when a capsule is to be placed in the
holder, a much smaller force has to be overcome that is the
case in the known spring-loaded mixing forces.
In another preferred embodiment, the actuator member is
1o mounted for rotation relative to the carrier portion and has
a spiral cam arrangement, and the retaining member has a fol
lower engaging the cam arrangement. This is of advantage
because the centre of gravity of the capsule holder does not
change in response to the position of the actuating member.
15 The spiral cam arrangement may be so shaped that the
retaining members are moved away from each other when the
actuator member is rotated in a direction opposite to the
rotational direction of the mixing device. With this struc-
ture, the clamping force exerted on the capsule by the
2o retaining member is assisted by forces which occur when the
mixing device rotates in the prescribed sense of rotation. In
this case, the spring, which may be provided, has the only
purpose of ensuring that the capsule is fixed when the rota-
tion starts.
25 For the practical manipulation of the capsule holder, it
is preferred that the cam arrangement extends through an
angle substantially between 45° and 180°.
According to another embodiment of the invention, the
carrier portion is formed as a disk having a guide slot for
3o the retaining member, the slot being open at the periphery of
the disk. This is useful to make the capsule holder easy to
assemble.
Providing the disk with an outward sloping peripheral
portion within the area of the guide slot ensures that the
35 retaining members, when completely moved apart, are somewhat

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tilted open so that the mixing capsule may be inserted and
removed particular easily.
Brief Description of the Drawing
Figure 1 is a sectional view of a capsule holder.
Figure 2 is a plan view of a carrier disk of the capsule
holder.
Figure 3 is a side view of one of a pair of retaining
arms of the capsule holder.
Figure 4 is a bottom view of the capsule holder taken in
to the direction of the arrow IV in Figure 1.
Detailed Description of Preferred Embodiments
In accordance with Figure 1, the capsule holder substan
tially consists of four components: a circular carrier plate
10, an actuator disk 11, and a pair of capsule retaining arms
12, 13 .
The lower side of the carrier plate 10 is provided with a
sleeve 15 for mounting on a shaft (not shown) which shaft may
be eccentrically mounted on a rotating disk of a rotary mix
ing device. The mixing device may have the structure
2o described in U.S. Patent No. 5,167,448.
According to Figures 1 and 2, the carrier plate 10 has
two guide slots 16 aligned along a common axis which inter-
sects the axis of the carrier plate 10. The guide slots 16
commence at a distance from the centre of the carrier plate
10 and are open at the periphery thereof. The spacing between
the inner ends of the guide slots 16 depends on the length of
the shortest capsule to be received by the retaining arms 12,
13. While the main area of the surface of the carrier plate
10 is plane, its peripheral portion 17 slopes outward.
3o As shown in Figure 3, the lower part of the retaining
arms 12, 13 is provided with lateral grooves 20 which cooper-
ate with lateral edges of the guide slots 16 provided in the
carrier plate 10 to form a slide. The mutually facing sides
of the retaining arms 12, 13 each have a recess 21 for

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receiving a respective end of a mixing capsule. A cylindrical
driving pin 22 is formed on the lower side of each retaining
arm 12, 13.
In accordance with Figures 1 and 4, the sleeve 15 of the
carrier plate 10 extends through a central bore 25 provided
in the actuator disk 11. The actuator disk 11 has a pair of
spiral cam slots 26 arranged rotationally symmetrical and
diametrically opposite each other, each extending though an
arc between 45° and 180°. Each cam slot 26 is engaged by the
to driving pin 22 of the respective retaining arm 12, 13. A
downward extending annular flange 27 integrally formed on the
actuator disk 11 has a knurled outer surface for easy manipu-
lation.
For inserting a mixing capsule, which is generally cylin
drical with rounded ends, the capsule holder is opened by
rotating the actuator disk 11 in the sense in which the driv
ing pins 22 of the retaining arms 12, 13 engaging the cam
slots 26 move away from the centre of the actuator disk 11;
in other words, the actuator disk 11 is rotated counter
2o clockwise in Figure 4. In the position in which the retaining
arms 12, 13 have their maximum spacing, they are in the slop-
ing peripheral portion 17 of the carrier plate 10 and may be
slightly tilted apart so that the capsule can be inserted
more easily.
The capsule is placed between the two recesses 21 of the
retaining arms 12, 13. A dispensing nozzle, which may be pro
vided at one end of the capsule, is placed in the slot 23
provided in one of the retaining arms 12, 13. For more com
fortable handling and for reasons of symmetry, both retaining
3o arms 12, 13 have such a slot 23, as shown in Figure 1.
Rotation of the actuator disk 11 in the opposite sense
will move the retaining arms 12, 13 toward each other so that
the inserted capsule is engaged and fixed in the recesses 21.
This movement is assisted by a spring 30 (shown in Figures 1
and 4) which connects the actuator disk 11 with the sleeve 15
of the carrier plate 10.

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The spirally curved cam slots 26 extend under such an
angle with respect to the radial direction that the retaining
arms 12, 13 are readily moved by rotating the actuator disk
11. However, if a force exerted on the retaining arms 12, 13
along the direction of the guide slots 16 in the carrier
plate 10, frictional forces acting on the actuator disk will
prevent any movement of the arms. The so formed gearing is
thus self-locking in one direction of force transmission.
According to Figure 4, the spiral cam slots 26 are so
1o shaped that their spacing from the centre of rotation of the
actuator disk 11 increases in the clockwise direction.
Depending upon the sense of rotation of the rotary disk of
the mixing device, this shape is so selected that the rota
tion produces forces on the capsule holder which seek to
rotate the actuator disk 11 in a sense in which the retaining
arms 12, 13 are moved toward each other. In this way, the
rotation of the mixing device assists the retaining forces
exerted on the capsule.
In a modification (not shown in the drawings) the actua
2o for disk 11 is fixed to a shaft mounted on the rotary disk of
the mixing device whereas the carrier plate 10 is rotatable
relative to the shaft. In this case, the retaining arms 12,
13 can be moved toward and away from each other by rotating
the carrier plate 10, the outer periphery of which may be
milled or knurled for easy manipulation.

Representative Drawing